Muffler construction

ABSTRACT

A muffler wherein a sound-attenuating member is slidably inserted within an outer shell, with the sound-attenuating member being formed from a sheet including a plurality of spaced parallel ribbons having alternating, longitudinally spaced crests and troughs, with the ribbons being interconnected by webs that are twisted throughout their length. The ribbons are positioned within the shell in a manner so as to present a substantial impediment to the flow of exhaust gases therethrough to thereby dampen the sound waves emanating from the exhaust system of an engine. Alternatively, the ribbons are arranged to produce less impediment of flow to the gases and greater sound-attenuating effect. The outer shell of the muffler may be a unitary tubular member that can be directly connected to the engine exhaust manifold. The muffler is disclosed in various configurations which may be used as a replacement unit for mufflers in present-day automobiles or, alternatively, to replace the entire muffler system. The disclosure also contemplates a simple and inexpensive method of forming the muffler from a plurality of tubes and one or more sections of sound-attenuating members by merely arranging and deforming the tubes to produce a plurality of chambers which are interconnected by passage means.

United States Patent Yancey [541 MUFFLER CONSTRUCTION [72] lnventor: Raymond W. Yancey, 880 Oak Spring Drive, Libertyville, 111. 60048 [22] Filed: Nov. 26, 1969 21 Appl. No.2 880,241

2,995,199 8/1961 Myers... 3,286,786 11/1966 Wirt ....l8l/53 X 3,365,863 l/1968 Greipel et al ..181/55 UX FOREIGN PATENTS OR APPLICATIONS 839,063 12/1938 France ..l8l/54 848,455 7/1939 France. ..181/55 475,047 10/1952 Italy ....l8l/72 548,563 9/1956 Italy ..181/72 Primary Examiner-Robert S. Ward, Jr. Attorney-Dressler, Goldsmith, Clement & Gordon Feb. 15, 1972 [5 7] ABSTRACT A muffler wherein a sound-attenuating member is slidably inserted within an outer shell, with the sound-attenuating member being formed from a sheet including a plurality of spaced parallel ribbons having alternating, longitudinally spaced crests and troughs, with the ribbons being interconnected by webs that are twisted throughout their length. The ribbons are positioned within the shell in a manner so as to present a substantial impediment to the flow of exhaust gases therethrough to thereby dampen the sound waves emanating from the exhaust system of an engine. Alternatively, the ribbons are arranged to produce less impediment of flow to the gases and greater sound-attenuating effect. The outer shell of the muffler may be a unitary tubular member that can be directly connected to the engine exhaust manifold.

The muffler is disclosed in various configurations which may be used as a replacement unit for mufilers in present-day automobiles or, alternatively, to replace the entire muffler system. The disclosure also contemplates a simple and inexpensive method of forming the muffler from a plurality of tubes and one or more sections of sound-attenuating members by merely arranging and deforming the tubes to produce a plurality of chambers which are interconnected by passage means.

36 Claims, 25 Drawing Figures PATENTEDFEBIS 1972 3.642.094

sum 1 or 2 INVENTOQ fgqvzolzdy gw/ccg BY-Q & 5 g Miami QTTOPNEFJ MUFFLER CONSTRUCTION BACKGROUND OF THE INVENTION Vehicle mufflers that are in common use today are bulky items which extend a substantial distance below the vehicle chassis, and oftentimes, the muffler is damaged when the vehicle travels over an obstruction. Furthermore, known mufflers are rather complex structural items, which make them expensive and difficult to fabricate. Prior art muffler constructions are also difficult to initially install, and replace when necessary, in that they comprise a series of tubular members that must be connected to one another and to the vehicle frame. The internal structure that is used in conventional mufflers to dampen the engine exhaust noises does not include means for allowing the structure to readily expand at elevated temperatures, and contract when the vehicle is not in use.

BRIEF SUMMARY OF THE INVENTION The muffler of the present invention includes a novel soundattenuating member that is formed from a sheet that has a series of transverse rows of longitudinally spaced openings, which divide the sheet into a plurality of spaced parallel ribbons that are interconnected by webs between the openings. The sheet is deformed to provide alternating, longitudinally spaced crests and troughs in the ribbons, and to give the webs a multiplanar torsional deformation. The twisted webs act as expansion joints allowing the ribbons of the sound-attenuating member to readily expand and contract at different temperature extremes.

In one embodiment of the invention, the sound-attenuating member is slidably inserted in a unitary outer shell that is connected directly to an engine exhaust manifold. The ribbons of the member are positioned in alignment with the length of the shell so as to present a substantial barrier to the passage of exhaust gases through the muffler, or transversely of the shell to produce substantial sound deadening. The tubular shell has an exhaust gas outlet end portion that is rectangular in cross section for slidable reception of the sound-attenuating member, and the entire outer shell has a low profile so as to extend only a minimum distance below the frame of a vehicle.

The sound-attenuating sheet is flexible, particularly along lines through the twisted webs, so that the member can be readily bent into an annular configuration for use in a muffler having tubular inner and outer shells.

Various embodiments are disclosed for forming muffler structures by deforming a plurality of tunes to predetermined configurations, arranging the tubes in telescoping relation to produce a plurality of chambers and placing the chambers in communication in several different ways to produce sinuous flow paths and resonator chambers for the gases.

Thus, with only minor changes in the parts and the arrangement thereof, it is possible to produce mufflers which are particularly adapted for exhaust gases having various types of sound-deadening characteristics, equalization of pressure differences of the exhaust gases and the removal of harmful toxic gases from the exhaust mixture. The utilization of circular tubes also allows for considerably increasing the capacity of the muffler with only a small increase in size of the unit.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE I DRAWINGS FIG. I is a broken schematic representation of an exhaust system for an internal combustion engine utilizing a typical prior art muffler structure;

FIG. 2 is a sectional view taken generally along line 2-2 of FIG. 1;

FIG. 3 is a view similar to FIG. 1, but illustrating a muffler formed in accordance-with the teachings of the present invention;

FIG. 4 is an enlarged fragmentary top plan view of the muffler illustrated in FIG. 3, with the top portion of the outer muffler shell being removed;

FIG. 4a is an enlarged top perspective view of the muffler of FIG. I, with portions of the outer muffler shell broken away;

FIG. 5 is a fragmentary top plan view of a modified muffler structure, with a portion of the top of the outer shell broken away;

FIG. 6 is a fragmentary perspective view of another muffler structure, with a portion of the outer shell removed;

FIG. 7 is a schematic central sectional view through the muffler of FIG. 6, and illustrating the path of gas flow therethrough;

FIG. 8 is a fragmentary perspective view of stillanother muffler structure, with the outer and intermediate shells broken away;

FIG. 9 is a schematic central sectional view through the muffler of FIG. 8, and illustrating the path of gas flow therethrough;

FIG. 10 discloses a central sectional view of a further muffler structure utilizing a single tube and a plurality of sections of sound-attenuating sheet;

FIG. 11 is a central sectional view of another embodiment of the muffler constructed according to the present invention;

FIG. 12 is a central sectional view illustrating an additional embodiment similar to FIG. 11 with the embodiment of FIG. 12 producing a modified flow path for the exhaust gases;

FIGS. 13a and 13b are broken central cross-sectional views illustrating a still further embodiment of the present invention which incorporates a resonator chamber and pollution control mechanism;

FIGS. 14a and 1411 are broken central sectional views illustrating a simplified version of a muffler incorporating resonator chambers;

FIGS. 15a and 15b are broken central sectional views disclosing a muffler similar to FIGS. 13a and 13b;

FIG. 15c is a fragmentary central sectional view disclosing an alternative embodiment for the outlet end of the muffler shown in FIGS. 15a and 15b;

FIGS. 16a and 16b are broken central sectional views disclosing a muffler particularly adapted for large displacement engines; and

FIGS. l7, l8 and 19 are central sectional views disclosing the configuration of the tubes prior to assembly of the muffler shown in FIGS. 16a and 16b.

DESCRIPTION OF THE PREFERRED EMBODIMENTS While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention and modifications thereof, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be pointed out in the appended claims.

Referring now to the drawings in detail, a typical prior art muffler structure is illustrated in FIGS. 1 and 2 as including an exhaust manifold 11 associated with an internal combustion engine 10, with a bent connecting tube 12 making a flanged connection 13 with the manifold 1]. Tube 13 communicates with a muffler 14 through an exhaust gas inlet pipe 15, and a tailpipe l7 communicates with a gas outlet pipe 16 at the opposite end of muffler l4. Muffler 14 is a bulky device which extends a substantial distance below the vehicle to present a significant impediment when the vehicle is traversing a bumpy terrain.

A first embodiment of the muffler structure of the present invention is indicated generally at 20 in FIG. 3, and it will be readily apparent from a visual comparison with FIG. 1 that the mufiler 20 is substantially less bulky than the prior art muffler 14. The muffler 20 includes a thin-low profile outer shell 21 in the form of an elongate, unitary tubular member that has an upwardly bent gas inlet end 23 which makes a flanged connection 22 with an exhaust gas manifold 11. The gas inlet end 23 of the outer shell 21 has a circular cross section and the gas outlet end 24 at the opposite end of the shell 21 has a rectangular cross section. As is evident from FIG. 3, the circular cross section portion of the outer shell 21 is smaller in diameter than the width of the rectangular portion 24. In this manner, the circular portion of the shell presents an inwardly facing abutment for limiting axial movement of a sound-attenuating member 25 toward the gas inlet end of the muffler 20.

The sound-attenuating member 25 is formed from a fiat, generally planar sheet having a plurality of transverse rows 27 I of elongate openings 28 that divide the member 25 into a plurality of spaced, longitudinally extending ribbons 29 that are connected by webs 30 between the openings 28. As can be seen in FIG. 4a, the sound-attenuating member is deformed so as to provide alternating longitudinally spaced crests 31 and troughs 32 in each of the ribbons 29, the the deforming step is performed in accordance with the teachings in my application Serf No. 767,305, entitled Article of Manufacture and Method of Making the Same, filed Oct. 14, 1968, now abandoned. The crests on the ribbons are aligned with troughs on an adjacent ribbon so as to define passages in the member that extend at right angles to the ribbons 29. The crests 31 are defined by upwardly converging ribbon portions 33, while the troughs 32 are defined by downwardly converging ribbon portions 34. In the embodiment of FIGS. 4 and 4a, the apexes of the crests and troughs are arcuate, and are curved about radii that are disposed on lines perpendicular to the length of ribbons 29. ,The webs 30 are provided at the transitional portion between the ribbon sections 33 and 34, and the webs 30 have "a multiplanar torsional deformation, such that one end portion 35 of the web is disposed in the plane of the transitional portion of one ribbon 29, while an opposite end portion 36 of the web is disposed in the plane of the transitional portion of an adjacent ribbon, with the intermediate portion 37 of the web being generally uniformly twisted between the end portions 35 and 36.

As can be best seen in FIG. 4, the member 25 has a width which is substantially the same as the interior dimension of the rectangular portion 24 of outer shell 21, and the distance between the apexes of crests 31 and troughs 32 is substantially the same as the height of the rectangular shell portion 24, as can be seen in FIG. 4a. The member 25 is slidably insertable within shell 21, with the ribbons 29 being parallel to the length of the shell in the embodiment of FIGS. 4 and 4a, and with the end of the member 25 bearing againstthe circular cross-sectional portion of the shell. A fastener 38, such as a screw, extends laterally through the rectangular portion 24 of the shell adjacent the gas outlet end thereof, and through one of the transverse passages in the member 25 to prevent axial displacement of the member 25. The webs 30 act as expansion joints allowing the sound-attenuating member 25 to move into snug engagement with the surrounding structure when the member is heated by the exhaust gases.

The ribbons 29 present a substantial barrier to the flow of exhaust gas through the muffler 20, thereby dampening the sound waves emanating from the engine 10. For an increased sound-attenuating effect, the ribbons 29 may be positioned at an oblique angle with respect to the length of muffler 20, as is shown in FIG. 5. The present invention contemplates that the sound-attenuating member may be formed of a plurality of separate sections, such as shown at 25a and 25b in FIG. 5, with the ribbons 29 of adjacent sections being inclined oppositely with respect to one another to maximize the interference with the flow of exhaust gas through the muffler.

A modified muffler structure is illustrated in FIGS. 6 and 7, and the muffler illustrated therein includes an outer generally cylindrically shaped shell 43 having an inlet pipe 44 of reduced diameter in communication with the gas inlet end thereof. An inner tubular member 45 is telescoped within an outer shell 43, and tubular member 45 has a closed end 46 adjacent the gas inlet end of the muffler, it being understood that the opposite end of member 45 is open to allow exhaust gases to pass outwardly therefrom. The end 47 of outer shell 43 remote from the gas inlet end is closed and is positioned in sealing engagementwith inner member 45, and member 45 includes a plurality of openings 48 inwardly of shell end wall 47 to allow the exhaust gases to flow through the annular chamber 49 between members 43 and 45, through the openings 48, and to the atmosphere.

A sound-attenuating member 50 is positioned in the annular chamber 49 between members 43 and 45, and member 50 is similar to the previously described sound-attenuating member 25 to the extent that it includes a plurality of spaced parallel ribbons 51 that are interconnected by integral webs 52 which are twisted throughout their length. As in the previously described embodiment, the ribbons 51 each include a plurality of alternating crests and troughs, but the sound-attenuating member 50 differs from the sound-attenuating member 25 in that the apexes 53 of the crests and the apexes 54 of the troughs present relatively broad surface areas that are positioned in face abutting engagement with members 43 and 45, respectively. Crest apexes 53 are curved about an axis that is parallel with the ribbons 51, with the radius of curvature being substantially equal to the radius of member 43; and in a like manner, the trough apexes 54 are curved about a radius that is parallel to the length of ribbons 51, with the radius being substantially equal to the radius of member 45. As with the previously described embodiment, the ribbons 51 present a substantial impediment to the flow of exhaust gases through the muffler, so as to dampen the sound of the engine to which the muffler is connected by dissipating the energy thereof. The longitudinally aligned twisted webs 52 allow the member 50 to be readily bent into'an annular configuration, since the twisted portions 52 act as hinge joints allowing the ribbons 51 to be disposed at different orientations with respect to one another. As with the previously described embodiment, the twisted webs 52 act as expansion joints allowing the member'50 to expand into snug engagement with members 43 and 45 when heated by the exhaust gases.

The embodiment of FIGS. 8 and 9 is similar to the embodiment of FIGS. 6 and 7 so that the same reference numerals have been used to designate corresponding elements, with the subscript a" having been added to the reference numerals in the embodiment of FIGS. 8 and 9. The muffler illustrated in FIGS. 8 and 9 differs essentially from that of FIGS. 6 and 7, in that an intermediate cylindrical tubular member 55 is positioned in the chamber 490 between members 43a and 45ato divide the chamber 49a into an annular outer zone 56 and an annular inner zone 57. A plurality of openings 58 are provided in member 55 to establish communication between the zones 56 and 57. The end 59 of member 55 adjacent the gas inlet end of the muffler is closed, so that a tortuous flow path is provided for the exhaust gases through the outer chamber zone 56, through openings 58, through the inner chamber zone 57, through openings 48a, and to the atmosphere through member 45a. Sound-attenuating members 50a are slidably inserted in each of the chamber zones 56 and 57, as is evident from FIG. 8. As in the embodiment of FIGS. 6 and 7, the

apexes of the crests and troughs of the ribbons in the sound-attenuating members are curved so as to conform to the tubular surfaces against which they abut.

In each of the three above-described embodiments, at least a portion of the sound-attenuating members is coated with a suitable substance for controlling the harmful effluent in the exhaust gases.

FIG. 10 discloses a further modification of a muffler structure incorporating the sound-attenuating member described hereinabove. The embodiment illustrated in FIG. 10 is specifically designed to be incorporated as original equipment to replace the bent connecting tube 12, the muffler l4 and the tailpipe 17, shown in FIG. 1.

In the embodiment illustrated in FIG. 10, the shell 60 has an intermediate portion 61 of circular cross section which receives an annular section 62 of the sound-attenuating member. The annular section 62 has its outer peripheral surface in contacting engagement with the inner surface of the intermediate portion of the shell. The inlet end 64 of the shell 60 is bent upwardly adjacent the forward end of the annular section 62 of the sound-attenuating member so as to define an abutment 66 which prevents forward axial shifting of the annular section 62. Alternatively, shell portion 64 may be smaller in diameter than shell 60.

Also, the outlet end of the substantially circular shell is deformed to a rectangular section 68 and has a further section 70 of the sound-attenuating member or sheet disposed therein. The deformation of the circular shell to a rectangular configuration defines a further abutment at 72 for the opposite end of the annular section 62 so as to prevent rearward axial shifting of the section 62 relative to the shell.

Thus, it will be seen that the entire muffler disclosed in FIG. can readily be manufactured by formation of the first annular section 62 to substantially the diameter of the shell, deforming the shell to provide the conically shaped transitional portion 74 rearward of section 67, deforming the outlet end of the shell to a rectangular configuration, slidably inserting the annular section of sound-attenuating sheet into the shell and bending the inlet end or forward end of the shell so as to lock the annular section of the sound-attenuating member or sheet in the intermediate portion of the shell. Thereafter, the rectangular section 70 of sound-attenuating member may be inserted into the outlet end of the muffler. In the assembled condition, the merging portion 74 of the shell between the circular intermediate section and the rectangular outlet end section defines an abutment 76 for the forward end of the rectangular section of the sound-attenuating member. As in the embodiment illustrated in FIG. 3, a fastener (not shown) may be inserted through the outlet end of the rectangular portion or section 68 so as to maintain the section 70 in fixed axial position relative to the shell.

If desired, either the annular section 62 or the rectangular section 70 may be arranged to have the passages formed between the respective crests and troughs 31 and 32 (FIG. 4a) disposed axially of the path of flow of the exhaust gases through the muffler so as to substantially decrease the impediment of the flow of gases through the muffler and increase the sound attenuation of the noises within the exhaust gases, as explained hereinabove.

A further modified form of the invention is disclosed in FIG. II in which the muffler shell is formed by deforming inner, intermediate and outer tubular members or tubes to define first and second inner and outer coaxial annular zones to produce a sinuous path for the flow of gases between the inlet and outlet of the muffler. In the embodiment illustrated in FIG. 11, the

nular zones 86 and 88, respectively.

The forward end of the intermediate tube 82 is closed by a forwardly tapered conical portion 90 which cooperates with the outer tubular member 84 to define a first passage means 92 connecting the outer annular zone 88 to the inlet end ofthe outer shell or muffler structure. Member 84 includes a frustoconically shaped portion 85 outwardly of portion 90, so that passage 92 uniformly tapers rearwardly. The tapered element 90 further cooperates with the forward end of the inner tubular member 80 to define second passage means 94 which connects the inner annular zone 86 with the outlet end of the muffler, it being understood that the inclined portion 90 deflects the exhaust gases rearwardly through member 80. Circumferentially spaced braces 96 are supported on a sleeve 97 to maintain an appropriate spacing at the forward end between the outer tubular member 84 and the intermediate tubular member 82.

Either of the annular zones 86 or 88 (or both) may have an annular section of the sound-attenuating sheet or member 98 supported therein. In the illustrated embodiment, the annular section of sound-attenuating member 98 is located in the inner annular zone and is illustrated as having the passageways disposed transversely to the path of flow of the gases through the zone. The outer tubular member 84 is again deformed adjacent the opposite ends of the annular zones to define an inlet 99 at one end of the muffler and to close the opposite ends of the annular zones 86 and 88 at the other end of the mufi'ler.

According to a further aspect of the present invention, the outer and inner annular zones are placed in communication with each other through passage means or openings 100 in tube 82 which are spaced from the rearward end of the respective annular zones. Thus, the exhaust gases passing through the inlet end 99 of the mufiler and along the outer annular zone 88 are received in the area 101 beyond the openings 100 and this area acts as a sound-attenuating buffer zone for absorbing noises of the exhaust gases. The stagnant gases in the buffer zone will absorb sound noises from the exhaust gases prior to the gases entering into the inner annular chamber and flowing forwardly to the second passage means 94 and thence through the inner tubular member to the outlet end of the mufiler. The particular muffler disclosed in FIG. II is designed as a replacement unit for the muffler l4 and has its inlet end 99 of a cross-sectional configuration substantially equal to that of the tube 12 and the outlet end adapted to receive the tailpipe 17. Alternatively, the outlet end could be deformed to a rectangular section as disclosed in FIG. 10 and the inlet end could be extended and bent upwardly to be connected directly to the exhaust manifold 11. One advantage of the embodiment illustrated in FIG. 11 is that a substantial portion of the heat of the exhaust gas is dissipated during the initial pass through the muffler, since the gas flowing through zone 88 is in direct heat exchange relationship with ambient atmosphere.

The embodiment illustrated in FIG. 12 is in many respects similar to that illustrated in FIG. 11 and the same reference numerals have been applied with the suffix a being appended to each of the reference numerals. In the embodiment illustrated in FIG. 12, the inner tube 80a is closed by a forwardly tapered portion a disposed adjacent the rearward end thereof, and the passage means 92a is in the form of circumferentially spaced openings in the tube 80a forwardly of element 90a. In an alternative embodiment, not shown, element 90a may be generally paraboloidically shaped. Preferably, in the alternative embodiment the generally paraboloidically shaped element is arranged to have its foci in line with openings 92a so as to direct the gases and sound waves into chamber 86a. The first passage means 92a connects the remote end of the inner annular zone 86a to the inlet end 99a of the muffler structure. The second passage means 94a is again in the form of circumferentially spaced openings extending through the intermediate tubular member 820 and the inner tubular member 80a rearwardly of member 90a, at the remote end of the annular zone 88a.

The forward end of the intermediate tubular member 82a terminates at a point spaced from the forward end of the outer annular zone 88a and cooperates with the inner and outer tubular members to define the third passage means a, Thus, the exhaust gases entering the inlet end 99a of the muffler will pass through tube 80a towards the outlet end and will be deflected by the tapered or parabolic portion 90a to flow outwardly through passage means 92a and forwardly along the inner annular chamber 86a. Shell 84a includes a frustoconically shaped portion 84a forwardly of intermediate shell 82a, and shell portion 84a presents an inclined deflector surface that is engaged by the forwardly flowing gases emerging from chamber 860. Tube 82a is spaced from shell portion 84a to define a pulse buffer zone 101a for absorbing sound noises from the exhaust gases. The direction of the flow of gases will be reversed so that the gases flow rearwardly in chamber 88a, through openings 94a and outwardly of the muffler.

A further modified muffler structure is shown in FIGS. 13:: and 13b which is specifically designed as original equipment to replace the three-piece structure heretofore considered necessary. The muffler disclosed in FIGS. 13a and 13b again includes an outer tube having a first relatively large diameter, an intermediate tube 112 having a second somewhat smaller diameter and an inner tube 114 having an even smaller third diameter. The respective tubes are telescopically arranged and are deformed from their original diameters to produce inner and outer annular zones as well as a resonator chamber at the forward end of the annular zone.

For this purpose, the intermediate tube 112 is inwardly deformed at spaced points 116 (FIG. 13a) and 118 (FIG. 13b) to the diameter substantially equal to that of the third diameter of the inner tube 114. Tube section 116 is frustoconically shaped, while tube section 118 is cylindrically shaped. The free end portion of tube 112 rearwardly of the inwardly deformed portion 118 is outwardly deformed at 120 and defines an outwardly flared frustoconically shaped portion having a diameter substantially equal to the inner diameter of the outer tube 110.

The forward end of the intermediate tube 112 has outwardly deformed flared frustoconically shaped portions 122 and 124 at spaced points which have a diameter substantially equal to the inner diameter of the outer tubular member 110. Tube 112 includes a perforated cylindrical portion 112a between outwardly flared portions 122 and 124. Thus, the outwardly deformed portions 120, 122 and 124 cooperate with the outer tube, when the two tubes are telescopingly positioned to produce first and second axially spaced chambers 123 and 121. Likewise, the inwardly deformed portions 116 and 118 cooperate with the inner tube to produce a third chamber 117 (FIG. 13b) which is substantially axially coextensive with the second chamber 121.

A plurality of circumferential openings 126 are produced in the connecting portion 127 between the inwardly deformed portion 116 and the outwardly deformed portion 122 of the intermediate tube to produce passage means-from the inside of the intermediate tube 112 to the second chamber 121 or the outer annular zone. Likewise, second passage means, in the form of circumferentially spaced openings 128, is formed in the intermediate tube 112 at a point spaced forwardly of cylindrical portion 118, so that the outer annular zone in in communication with the third chamber 117 of the inner annular zone at a point spaced forwardly from the remote end of the outer annular zone. The inner tube 114 has third passage means in the form of circumferentially spaced openings 130 formed adjacent the forward end thereof, and the forward end of tube 114 includes a conically shaped portion 132. Thus, the path of flow for gases entering the inlet end 134 of the muffler is through the forward end of the intermediate tube 112 with the first chamber 123 between the outwardly deformed portions 122 and 124 acting as a resonator chamber. The exhaust gases are then deflected outwardly by the tapered element 132 through the first passage means formed by openings 126, and the gases flow rearwardly along the second chamber 121, with the remote end of the second chamber or annular zone acting as a sound-deadening pulse buffer zone 135. The direction of the flow path for the gases is then reversed and the gases flow through openings 128 and forwardly through the third chamber or inner annular zone 117. The gases then pass into the inner tube 114 through the third passage means 130 and flow rearwardly along the inner tube to the outlet end of the muffler in order to maintain the intermediate tubular member or tube 112 in an appropriate position, the outer tubular member is preferably deformed to a rectangular configuration 136 at the outlet end thereof, with a transitional section 136a defining an abutment for the outwardly flared portion 120 to prevent rearward movement of the intermediate member. Also, the forward end of the outer tubular member 110 is bent adjacent the tapered portion 124 of the intermediate tube and produces a further abutment to prevent axial shifting of the intermediate tube relative to the outer tube. The inner tubular member 114 is held in place by a drive fit connection between a reduced diameter forward portion 114a thereof, and the inwardly extending portion 116 of the intermediate tube, as can be seen in H6. 13a.-

It will be appreciated that the entire muffler may be constructed by simply deforming the intermediate tube to the configuration described, producing the plurality of openings at appropriately spaced locations in the intermediate as well as in the inner tube, closing the forward end of the inner tube and telescoping the respective tubes to the position shown in the drawing. Thereafter, the forward and rear or inlet and outlet ends of the outer tube or shell may be deformed to maintain the appropriate relationship between the tubes.

As in the previous embodiments described, the muffler structure again incorporates a sound-deadening sheet or sound-attenuating member of the type described above. In the embodiment illustrated in FIGS. 13a and 13b, a first section of sound-attenuating sheet 140 is slidably received in the rectangular section 136 adjacent the outlet end of the muffler. The ribbons of the sound-attenuating member 140 are disposed longitudinally of the rectangular section so as to locate the passage means defined between the troughs and crests transversely of the path of flow of gasses. Thus, this section of sound-attenuating sheet will produce the greatest impediment to the flow of gases through the outlet end of the muffler. A further section of sound-attenuating sheet 142 is located in the inner annular zone defined between the inner and intermediate tubes 114 and 112, and the ribbons of the sound-attenuating sheet extend circumferentially of the annular zone so as to locate the passage means between the crests and troughs parallel to the path of flow of the gases through the inner annular zone.

An additional annular section of sound-attenuating sheet 144 is located adjacent the inlet end of the outer tube 110 and supports a pollution control material for removing the harmful gases from the exhaust gases. By way of example, a pollution control material, such as the AL O V O CuO mixture disclosed in U.S. Pat. No. 3,438,721, can be carried by sheet 144. The structure of sheet 144 provides an excellent vehicle for this type of material because of the large surface area that it presents, which can quickly come up to reaction temperature. Illustratively, the sheet 144 can be coated with a slurry and then baked on at a suitable temperature. Alternatively, the interstices of the sheet could hold spheres, cylinders, rectangular rods, cubes or burr-shaped parts formed of a suitable pollution control material, as is shown at 145 in FIG. 13a. Still further, the sheet 144 itself could be formed of a suitable alloy or composite material of sound-deadening material that upon heating would produce an oxide film of comparable analysis and equivalent to that disclosed in the above-mentioned patent.

Thus, the simple muffler structure disclosed in FIGS. 13a and 13b is capable of removing the harmful materials from the exhaust gases and reducing the sound noise to an acceptable level. The specific arrangement of the intermediate section of sound-attenuating sheet 142 considerably enhances the reduction of the noise level since the sound waves within the exhaust gases have a tendency to radiate or propogate transversely or normal to the direction of flow of the gases. By arranging the passage means of the section of sound-attenuating member axially of the path of flow, the sound waves will tend to radiate outwardly into engagement with the respective ribbons defining the respective passage means. Of course, if it is desired to increase the resistance to the flow of gases within the annular zone, it is contemplated that the passage means or the ribbons could be located at an angle with respect to the path of flow of the gases to produce such a result.

A still further modified form of the invention is disclosed in FIGS. 14a and 14b which again includes an outer tube 150, an intermediate tube 152 and an inner tube 154. The intermediate tube 152 has a plurality of apertures 156 therein and is located adjacent the forward end of the intermediate portion of the outer tube 150. The area between the opposite ends of the intermediate tube 152 and the outer tube is closed by suitable means, such as by deforming the intermediate tube outwardly at opposite ends so that they engage the inner diameter of tube 150, or by locating a pair of discs 158 to define a resonator chamber 160.

A first section of gas-deflecting and sound-deadening sheet 162 is located adjacent the forward end of the tube 152, and a second section 164 is located adjacent the opposite end thereof. The third tube 154 is telescopically received in a reduced area portion 166 adjacent the rearward end of the tube 150, and the area between the forward edge of the intermediate tube 154 and outer tube 150 is closed by an annular 7 disc 168. A plurality of apertures 170 are produced in the intermediate tube 154 and place the chamber 172 in communication with the inside of the tube 154.

Thus, the muffler disclosed in FIGS. 14a and 14b has first and second sections of gas-deflecting and sound-deadening sheet on opposite sides of a resonator chamber 160 and a second resonator chamber 172 is located adjacent the rear end of the muffler structure. The entire muffler may again be assembled by telescoping the appropriate sections of the annular sheet and the tubes in a proper manner and deforming the outer shell. The annular section 162 of material may again incorporate a pollution control material. Additionally, the disclike portions 158 and 168 may be eliminated, and the tubes 156 and 154 may bear directly against the sheets 162 and 164.

A simplified version of the embodiment illustrated in FIGS. 13a and 13b is disclosed in FIGS. 15a and 15b. In this embodiment, it is only necessary to deform one tube (the outer) to produce a muffler having inner and outer annular zones, a pulse buffing zone, and a resonator chamber adjacent the forward end.

Thus, the embodiment illustrated in FIGS. 15a and 15b includes an outer tube 180, an intermediate tube 182, and an inner tube 184. The forward end of the intermediate tube is closed by a conically shaped portion 186, which cooperates with the outer annular tube 180 to produce first passage means 188 and with the inner tube to produce second passage means 190. The appropriate spacing between the forward ends of the respective tubes is maintained by radial braces 196 to define an outer annular zone 192 and an inner annular zone 194.

The opposite'ends of the annular zones are closed by an annular disc 197 which engages an abutment 198 (FIG. 15b) produced by inwardly deforming the outer tube 180. A plurality of circumferentially spaced openings 199 are produced in the intermediate tube 182, and are spaced axially forwardly from the annular disc 197 so as to produce a pulse buffer zone 195 between the end of the outer annular zone or chamber. The openings 199 produce communication between the two annular chambers, so that the gases flowing rearwardly in chamber I92 can flow forwardly in chamber 194.

The resonator chamber is formed between the inlet end of the muffler and the inlet to the annular zone 192. For this purpose, an apertured sleeve 200 has outwardly directed flanges 202 adjacent opposite ends thereof and is slidably received into the forward end of the outer tube 180. The rear flange 202 engages an abutment defined by an inwardly directed rib 204 on the outer tube 180 and the forward end of the tube 180 is bent adjacent the forward flange so as to maintain an appropriate positioning of the sleeve 200 relative to the outer tube 180.

The opposite end of the outer tube 180 is deformed into a rectangular section 206 which has a section 208 of the abovedescribed sheet disposed therein. A further chamber 109 is defined between the rectangular section and the annular disc 197 with the remote end of the inner tube 184 extending into the chamber. The chamber 209 tapers rearwardly, and acts as a mixing chamber to insure that the gases exhausted from the outlet end of the muffler exit at a substantially constant pressure. This will result from the fact that the impediment to the flow of gases produced by the section 208 will result in a turbulence adjacent the outlet end of the inner tube, and the tapered end of the outer tube will further increase this turbulence and result in an equalization of the pressure of gases exiting from the muffler structure.

If desired, the outlet end of the muffler structure may be modified to that shown in FIG. 15c where a second resonator chamber 212 is formed by extending the outlet end of the inner tube 184a and producing an outwardly flared portion 214 which is in engagement with the inner surface of the outer tube 180a.

A further modification of the-muffler system of the present invention is disclosed in FIGS. l6l9. The particular construction disclosed in this embodiment is particularly adapted for engines having a relatively large displacement. A construction disclosed in FIGS. 16-19 incorporates first and second axially spaced pairs of annular chambers or zones with resonator chambers located between the pairs of annular zones and on opposite ends of each annular zone.

As with several of the previous embodiments, the entire muffler may be constructed by deforming three circular tubes to define the various chambers between the inlet and outlet ends thereof. Thus, the muffler includes an outer tube 230, an intermediate tube 232 and an inner tube 234 respectively having first, second and third diameters. In the formation of the muffler structure illustrated in FIGS. 16a and 16b, the intermediate tu'be 232 (FIG. 18) is outwardly deformed at 239, 240, 241 and 242 to substantially the inner diameter of the outer tube 230. Also, the intermediate tube 232 is inwardly deformed at 243 to substantially the outer diameter of the inner tube 234. The intermediate tube has a plurality of openings 244 between the defonned portions 239 and 240 and has first, second, third and fourth circumferentially spaced groups of openings 245, 246, 247, and 248 respectively located at axially spaced points adjacent the outwardly deformed portions 240, 241 and 242.

The inner tube 234 has its forward end closed at 250 by a forwardly tapered conically shaped element, and tube 234 is outwardly deformed at 251 at a point spaced axially rearwardly from the inlet end. Tube 234 is outwardly deformed at 252 adjacent the opposite or rearward end thereof. The outwardly deformed portions 251 and 252 have a diameter substantially equal to the inner diameter of the intermediate tube 232. The inner tube 234 is further inwardly deformed at 253 to substantially close the tube.

The inner tube further has a first group of circumferentially spaced openings 254, adjacent the forward end thereof; a second group of circumferentially spaced openings 255, disposed forwardly of the inwardly deformed portion 253; and a third group of circumferentially spaced openings 256 on the opposite side of the inwardly deformed portion 253. Also, each of the outwardly deformed portions 251 and 252 has a plurality of openings 257 disposed therein.

In assembling the muffler, the inner tube or tubular member 234 is axially inserted into the rear end of the intermediate tube so as to locate the forward end 2500f the tube in drivefit engagement with the inwardly deformed portion 243 of the intermediate tube. The outwardly deformed portions 251 and 252 have an axial dimension slightly greater than the axial dimension of the outwardly deformed portions 241 and 242 of the intermediate tube so as to define axially spaced first and second chambers 260 and 261. The adjacent ends of the outwardly deformed portions 251 and 252 on the inner tube likewise cooperate with the intermediate tube to define a third chamber 262. Furthermore, the inwardly deformed portion 243 of the intermediate tube and the adjacent end of the outwardly deformed portion 251 of inner tube 234 cooperate to define a fourth chamber 263.

With the inner tube assembled in the intermediate tube as described above, the two tubes are axially received into one end of the outer tube 230 prior to deformation thereof, and the subassembly of inner and intermediate tubes is located in an intennediate portion of the outer tube. In this position, the intermediate tube and the outer tube cooperate to define fifth, sixth and seventh chambers 264, 265 and 266. Thereafter, the outlet end of the outer tubular member is deformed to a rectangular cross section 270 and a sheet of sound-deadening member 272 is axially slid into the open end thereof. Again, suitable fastener means may extend transversely through the outer end of the rectangular section to maintain the. gasdeflecting and sound-deadening member in the appropriate position within the rectangular section 270.

The opposite end of the outer tubular member 230 is then bent upwardly adjacent the outwardly flared portion 239 of the intermediate tube and the entire assembly is maintained in a substantially fixed position. In the assembled condition shown in FIGS. 16a and 16b, the chamber 264 defines a first resonator chamber cooperating with the inlet end of the muffler while the two chambers 263 and 265 are substantially coextensive with each other to define a first group of inner and outer annular zones. The outer annular zone 265 is in communication with the inlet end of the muffler through the openings 245, while the two annular zones 263 and 265 are in communication with each other through openings 246. It will be noted that the openings 246 are spaced from the remote end of the outer annular zone defined by chamber 265, so as to produce a sound-deadening, pulse buffer zone adjacent the rear end of the first outer annular zone. The gases received in the inner annular zone 263 travel forwardly towards the inlet end of the muffler structure and exit through the openings 254 in the inner tube 234. The path of flow of the gases then continues rearwardly through the inner tube 234, where the pressure of the gases is further equalized by having some of the gases received through openings into the annular zone 260, which defines a second resonator chamber. The inwardly deformed portion 253 on the inner tube prevents the flow of gases therethrough and, thus, the gases are directed outwardly through the coextensive openings 255 and 247 and enter the forward end of the chamber 266. The gases fiow rearwardly in chamber 266, and are then received through the openings 248 and flow forwardly along the inner annular zone defined by chamber 262. Again, the openings 248 are spaced from the remote end of the second outer annular zone to define a further pulse buffer zone.

The flow of gases continues forwardly along the inner annular zone defined by chamber 262 through the openings 256 which are spaced from the forward end of the inner annular chamber 262 to define a further sound-deadening pulse buffer zone. Before the exhaust gases are received in the outlet end of the muffler structure, the gases are again directed through a further resonator chamber, defined by chamber 261, so as to further equalize the pressure of the gases.

Thus, it will be appreciated that the present invention provides a simple and efficient method and apparatus of producing a plurality of types of muffler structures which are capable of being incorporated into any new automobile having various sizes of displacement for the engines and may also readily be designed to be utilized as a replacement unit.

What is claimed is:

l. A muffler comprising: an outer shell having a gas inlet at one end, adapted to receive exhaust gases from an internal combustion engine or the like, and a gas outlet at an opposite end; a gas-deflecting and sound-deadening sheet disposed in said shell, said sheet having a plurality of transversely spaced rows of openings, each row of openings being separated by a ribbon portion and the openings in each row being separated by a web portion, each ribbon including alternating, longitudinally spaced crests and troughs, the crests extending upwardly from a reference plane the the troughs extending downwardly from the reference plane, the transitional portion of each ribbon between the crests and troughs extending at an angle with respect to the reference plane, the crests on each ribbon being aligned with a trough on an adjacent ribbon whereby the aligned transitional portions of adjacent ribbons are disposed at angles that are inclined oppositely with respect to said reference plane, said webs each having a first end portion merging with a transitional portion of one ribbon and a second end portion merging with the aligned transitional portion of an adjacent ribbon, the intermediate portion of each web between its end portions being twisted throughout its length. i

2. A muffler as set forth in claim 1 wherein said ribbon portions are disposed at an angle of 90 with respect to the width of said shell, whereby said ribbon portions are aligned with the length of said shell.

3. A muffler as set forth in claim I wherein said crests and troughs are positioned in engagement with opposite sides of said shell.

4. A muffler as set forth in claim 1 wherein the gas inlet end of said shell is circular in cross section and the gas outlet end of said shell is rectangular in cross section, the circular portion of said shell being smaller than the rectangular portion of the shell to provide an abutment engageable with the forward end of said sheet.

5. A muffler as set forth in claim 4 wherein a fastener extends through the rectangular portion of the shell to provide an abutment engageable with the rearward end of the sheet.

6. A muffler as set forth in claim 1 wherein the intermediate portion of said shell and said gas outlet end are rectangular in cross section, the width of said sheet being substantially equal to the width of said shell and the distance between the apexes of said crests and troughs being substantially equal to the height of said shell, whereby said sheet is snugly received within the rectangular portions of the shell.

7. A muffler as set forthin claim 1 in which said shell is defined by an inner tubular member positioned in telescoping relationship within an outer tubular member to define an annular chamber therebetween, the outer tubular member having a closed end remote from the gas inlet end of the shell, the inner tubular member having a closed end adjacent the gas inlet end of the shell and an open end extending outwardly from the closed end of said outer tubular member at the gas inlet end of the shell, there being passage means in said inner tubular member establishing communication between said chamber and said inner tubular member, and wherein said sheet has an annular configuration so as to be received in said annular chamber.

8. A muffler as set forth in claim 7 in which said inner tubular member has an intermediate tubular member disposed concentrically outwardly thereof, said intermediate tubular member being disposed concentrically inwardly of said outer tubular member to divide said chamber into inner and outer annular zones, said intermediate tubular member having both of its ends closed and passage means therein establishing communication between said zones; and wherein said sheet is defined by a first annular section slidably insertable in said inner zone and a second annular section slidably insertable in said second zone.

9. A muffler as set forth in claim 1 wherein said shell is a unitary member that is circular in cross section at the gas inlet end thereof, and that is rectangular in cross section at the gas outlet end thereof. 7 I

10. A muffler as set forth in claim 1 wherein a coating is provided on at least a portion of said sheet for controlling the harmful effluent in the exhaust gas. I i

11. A muffler as set forth in claim 1, in which said shell is defined by inner, intermediate and outer tubular members positioned in telescoping relationship and cooperating to define inner and outer coaxial, annular zones; first and second passage means placing adjacent ends of respective zones in communication with said inlet end and said outlet end; and third passage means spaced from said first and second passage means and placing said zones in communication with each other.

12. A muffler as set forth in claim 11 in which one of said annular zones has an annular section of said sheet disposed therein.

13. A muffler as set forth in claim 11 including the further improvement of means cooperating with said outer tubular member between the inlet of said shell and said annular zones to define a resonator chamber.

14. A muffler as set forth in claim 11 in which said intermediate tubular member has a tapered element closing the inlet end thereof, said tapered element cooperating with said outer tubular member to define said first passage means and said inner tubular member to define said second passage means; said third passage means includes apertures spaced from said opposite end whereby the outlet end of said outer annular zone defines a pulse buffer zone; and said outer tubular member is rectangular in cross section between the outlet end of said inner tubular member and the outlet end of said muffler, said rectangular section having said sheet therein; and in which said muffler includes means defining a resonator chamber between said inlet end and said tapered element and including an apertured sleeve coaxial with said outer tubular member.

15. A muffler as set forth in claim 14 in which said last means includes anintegral extension at the inlet end of said intermediate tube, said extension having an outwardly tapered portion at the free end engaging said outer tubular member and having a plurality of apertures communicating with a chamber defined between said extension and said outer member; said intermediate tubular member has a second outwardly flared portion engaging said outer tubular member at a point axially spaced from said third passage means to define said annular pulse buffer zone adjacent the remote end of said outer annular zone; and said inner tubular member has a forwardly tapered element closing the forward end thereof for deflecting gases from said intermediate tubular member toward said outer annular zone.

16. A muffler as set forth in claim 15 including the further improvement of an annular section of said sheet supported adjacent the forward end of said resonator chamber, said annular section supporting a catalyst for effecting the chemical composition of theexhaust gases.

17. A muffler as defined in claim 11 in which said inner tubular member has a tapered element closing the inlet end portion; said inner tubular member has an outwardly deformed portion spaced from said closed end and cooperating with said intermediate tubular member to define the remote end of said inner annular chamber; said intermediate tubular member has an inwardly deformed portion cooperating with said inner tubular member adjacent said closed end portion to define the forward end of said inner annular chamber, said intermediate tubular member extending beyond said closed end portion and having spaced outwardly deformed portions cooperating with said outer tubular member to define a resonator chamber. said intermediate tubular member having openings placing said resonator chamber in communication with said inlet end; said first passage means is located adjacent said inwardly deformed portion of said intermediate tubular member to place said outer annular zone in communication with said inlet end; and said third passage means is spaced from the opposite end of said outer annular zone to define a sound-attenuating buffer zone.

18. A muffler as defined in claim 1 in which said shell comprises a circular member having an annular section of said sheet located in contacting engagement with the inner surface of an intermediate portion thereof; said circular member being deformed to a rectangular section adjacent the outlet end thereof and having a section of said sheet disposed therein; and said circular member being bent at the opposite end of said intermediate portion whereby said annular section is maintained in substantially fixed position relative to said shell.

I). A muffler as defined in claim 1 in which at least a section of said sheet has said ribbon portions extending transversely of said shell.

20. A muffler as defined in claim 1 in which said sheet is slidably inserted in said shell and said ribbon portions are disposed at an angle with respect to the width of said shell.

21. A muffler as defined in claim 1 in which said shell comprises an outer tubular member having reduced area portions on opposite ends thereof; first and second annular sections of said sheet located within said outer tubular member and having adjacent ends in axially spaced relation, said first section having its opposite end in engagement with an abutment defined by one of said reduced area portions; a tube having an intermediate portion in sealing engagement with said reduced area portion, said tube having a free end extending into said tubular member and engaging the-opposite endof said second annular section, said tube cooperating with said tubular member to define a second resonator chamber in communication with the inside ofsaid tube.

22. A muffler comprising outer tubular member having a forward inlet endand a rear outlet end; an intermediate and an inner tubular member; said tubular members cooperating to define substantially coextensive inner and outer annular zones; first and second passage means communicating with adjacent ends of said inner and outer annular chambers and connecting a first of said zones with said inlet end and a second of said zones with said outlet end; third passage means interconnecting said zones, said third passage means being spaced from the opposite end of said first of said zones whereby exhaust gases received through the inlet end of said muffler pass through said first passage means and move along a path in one of said zones and pass through said third passage means and move along the other of said zones in the opposite direction and whereby the area between said third passage means and said first of said zones acts as a sound-deadening pulse buffer zone to absorb sound noises from said gases; and a sound-attenuating sheet in said outer tubular member between said inlet and outlet ends.

23. A muffler as defined in claim 22, including a tapered member closing the forward end of said inner tubular member with said first and second passage means located adjacent said end and respectively placing the forward end of said outer annular zone in communication with said inlet end and the forward end of said inner annular zone in communication with said outlet end; and in which said intermediate tubular member extends forwardly of said inner tubular member and has spaced portions cooperating with said outer tubular member to define a resonator chamber, and said intermediate tubular member has openings between said portions placing said resonator chamber in communication with said inlet end.

24. A muffler as defined in claim 23, including the further improvement of said inner and intermediate tubular members each having first and second spaced, substantially coextensive outwardly deformed portions adjacent the rear end of said annular zones defining second and third spaced resonator chambers in communication with said inner tubular member; said inner tubular member having an inwardly deformed portion substantially closing said inner tubular member adjacent the rear end of said second resonator chamber; said tubular members cooperating to define second annular inner and outer zones between said second and third resonator chambers, said second annular inner and outer zones respectively in communication at the forward ends thereof with said inner tubular member upstream and downstream of said inwardly deformed portion; said intermediate tubular member having radially spaced openings placing said second outer annular zone in communication with said inner annular zone spaced from the rear endof said second outer annular zone to define a second buffer zone and said communication between said second inner annular zone and said inner tubular member being spaced from the forward end of said second inner annular zone to define a third pulse buffer zone.

25. A muffler as defined in claim 22 in which said intermediate member has a forwardly tapered closed end which cooperates with said outer tubular member to define said first passage means and said inner tubular member to define said second passage means.

26. A mufiler as defined in claim .25 in which said inner tubular member extends beyond the rear end of said intermediate tubular member and in which said outer tubular member is cireular'in cross section and theoutlet end thereof is rectangular in cross section and has a section of said soundattenuating sheet therein; and in which said outer tubular member has an apertured sleeve cooperating with said outer tubular member to define a resonator chamber between said inlet end and said first passage means.

.27. A muffler as defined in claim 22 in-which said inner tubular member has a forwardly tapered element adjacent the rear end of said zones; said first and second passage means beinglocated adjacent said tapered element and connecting said inlet .end to said inner annular zone and said outlet end to said outer annular zone; said intermediate tubular member tubular member to define said third passage means.

28. Amethod of forming a muffler having an inlet end and an outlet end for exhaust gases and a sinuous flow path for said gases between said ends by deforming inner, intermediate and outer tubes which comprises the steps of deforming said intermediate tube outwardly at first, second and third axially spaced locations which cooperate with said outer tube to produce first and second axially spaced chambers when said tubes are arranged in telescoping relation; forming apertures in said intermediate tube to place the inside of said tube in communication with said first chamber when the tubes are arranged in telescoping relation; producing first passage means through said intermediate tube adjacent one end of said second chamber and second passage means spaced forwardly of the second outward deformation; deforming at least one of said intermediate and inner tubes to produce a third chamber having one end in communication with said second passage means when said tubes are arranged in telescoping relation; closing one end of said inner tube and producing third passage means adjacent said'closed end; telescoping said inner tube into said intermediate tube to locate said closed end adjacent said first passage means and said deformed portions of said at least one of said intermediate and inner tubes to produce said third chamber; telescoping said intermediate tube into said outer tube to produce said first and second chambers; locating a gas-deflecting and sound-deadening sheet between the inlet and outlet ends of said outer tube; and deforming opposite ends of said outertube toienclose said intermediate and inner tubes between said opposite ends and produce a sinuous flow path for exhaust gases into one end of said intermediate tube with said first chamber acting as a resonator chamber, through said second chamber with the opposite end of said second chamber acting as a sound-deadening buffer zone, through an outlet end for exhaust gases and a sinuous path between said ends for said gases by deforming inner, intermediate and outer tubes whic comprises deforming and telescopingly positioning said tubes to produce substantially coextensive outer and inner coaxial annular zones respectively defined between said outer and intermediate tubes and saidintermediate and inner tubes; placing adjacent ends of said zones in communication with said inlet and outlet ends, respectively; producing passage means spaced from said adjacent ends of said zones to place said zones in communication with each other whereby gases received from the inlet end fiow in opposite directions in said annular zones to produce said sinuous path and the opposite end of the annular zone produces a sound-attenuating buffer zone for the exhaust gases; and locating a sound-attentuating member between said inletand outlet ends of said mufiler. I v

33. A method as defined in claim 32 further including the step of closing said inner tube adjacent the ends of said annular zones which are remote from said inlet end of said muffler; placing said inner annular zone in communication with said inlet end adjacent the inlet side of said closed portion and said outer annular zone in communication with the outlet side of said closed portion; terminating said intermediate tubespaced from the end of said outer annular zone and from said inner said second passage means and along said third chamber,and

through said third passage means and said inner tube to said outlet. e

29. A method as defined in claim 28 in which said outlet end of said outer tube is deformed to a rectangular cross section and at least a'section of said sheet is located in said rectangu-' lar section.

30. A method as defined in claim 28 in which said deforming of at least one of said intermediate and inner tubes includes' inwardly deforming spaced portions of said intermediate tube to engage said innertube in the telescoped position.

31. A method as defined in claim 28 in which said outward deforming of said intermediate tube includes outward deformation at a fourth location axially spaced from said third location and inward deformation adjacent said first outward deformation; and in which said inner tube is outwardly deformed at first and second locations and is inwardly deformed adjacent said first outward deformation; the further improvement of producing apertures in each of said outwardly deformed portions of said inner tube and first and second groups of openings on opposite sides of said inwardly deformed portion; and producing third and fourth groups of openings respective ly adjacent said third and fourth outwardly deformed portions of said intermediate tube; said third and fourth outward deformations of said intermediate tube cooperating with said first and second outward deformations of said inner tube to define second and third resonator chambers and outer and inner annular zones in the assembled condition; said first group of openings being aligned to define an inlet to said outer annular zone; said second openings in said intermediate tube connectand outer tubes; and locating an annular section of said soundattenuating member in one of said annular zones whereby the exhaust gases flow along said inner, tube to said closed portion, towards said inlet end along said inner annular zone and towards said outlet endalong said'outer annular zone and whereby said adjacent end of said outer annular zone acts as said sound-attenuating buffer zone. I i 34. A method as defined in claim 32-including the further step of producing'a closed tapered portion on the inlet end of said intermediate tube which cooperateswith said outer tube to connect the outer annular zone to said inlet and with said inner tube to connect said inner annular zone with said outlet.

35. A method as defined in claim 32 including the further steps of producing a closed forward taper on the inlet end of said inner tube; inwardly deforming said intermediate tube 40 into engagement with said inner tube; placing said outer annular zone in communication with said inlet end and said inner annular zone in communication with said outlet end on opposite sides of said closed forward'taper; extending said intermediate tube from said closed forward taper and outwardly deforming spaced portions of the extension into engagement with said outer tube to produce a resonator chamber in' communication with said inlet end.

36. A method of forming a muffler from outer, intermediate and inner tubes, each having forward and rear ends and, respectively, having first, second and third diameters which comprises: the steps of deforming said intermediate tube at first and second axially spaced locations adjacent said first end to substantially said first diameter, and third and fourth axially spaced locations; deforming one of said intermediate and inner tubes at axially spaced first and second points to the diameter of the other of said tubes; producing passage means 0 jacent said closed end; positioning said tubes in telescoping relation with the deformations of the intermediate tube cooperating with the outer tube to define a resonator chamber and an outer annular zone between said outer and intermediate tubes, and the deformations of the tubes cooperating to define an inner annular zone; said passage means in said intermediate tube placing the intermediate tube in communication with said resonator chamber and the forward end of said outer annular zone, said passage means also placing the remote end of said outer annular zone in communication with said inner annular zone at the remote end thereof.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Inventor(s) RAYMOND w. YANCEY It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 13, "the the" should read and the Column 7, line 32, in in" should read Column 8, line 12, "gasses" should read gases Column 9, line 55, 109" should read 209 Column ll, line 55, "the the" should read and the Column 1 line '49, after "with said" add second Column 1, line 47, "tunes" should read tubes Insert the attached sheets of drawings as part of the Letters Patent:

Signed and sealed this 27th day of February 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents IOHM PC -1050 (10479) Uscomhhuc 03704'0 

1. A muffler comprising: an outer shell having a gas inlet at one end, adapted to receive exhaust gases from an internal combustion engine or the like, and a gas outlet at an opposite end; a gas-deflecting and sound-deadening sheet disposed in said shell, said sheet having a plurality of transversely spaced rows of openings, each row of openings being separated by a ribbon portion and the openings in each row being separated by a web portion, each ribbon including alternating, longitudinally spaced crests and troughs, the crests extending upwardly from a reference plane the the troughs extending downwardly from the reference plane, the transitional portion of each ribbon between the crests and troughs extending at an angle with respect to the reference plane, the crests on each ribbon being aligned with a trough on an adjacent Ribbon whereby the aligned transitional portions of adjacent ribbons are disposed at angles that are inclined oppositely with respect to said reference plane, said webs each having a first end portion merging with a transitional portion of one ribbon and a second end portion merging with the aligned transitional portion of an adjacent ribbon, the intermediate portion of each web between its end portions being twisted throughout its length.
 2. A muffler as set forth in claim 1 wherein said ribbon portions are disposed at an angle of 90* with respect to the width of said shell, whereby said ribbon portions are aligned with the length of said shell.
 3. A muffler as set forth in claim 1 wherein said crests and troughs are positioned in engagement with opposite sides of said shell.
 4. A muffler as set forth in claim 1 wherein the gas inlet end of said shell is circular in cross section and the gas outlet end of said shell is rectangular in cross section, the circular portion of said shell being smaller than the rectangular portion of the shell to provide an abutment engageable with the forward end of said sheet.
 5. A muffler as set forth in claim 4 wherein a fastener extends through the rectangular portion of the shell to provide an abutment engageable with the rearward end of the sheet.
 6. A muffler as set forth in claim 1 wherein the intermediate portion of said shell and said gas outlet end are rectangular in cross section, the width of said sheet being substantially equal to the width of said shell and the distance between the apexes of said crests and troughs being substantially equal to the height of said shell, whereby said sheet is snugly received within the rectangular portions of the shell.
 7. A muffler as set forth in claim 1 in which said shell is defined by an inner tubular member positioned in telescoping relationship within an outer tubular member to define an annular chamber therebetween, the outer tubular member having a closed end remote from the gas inlet end of the shell, the inner tubular member having a closed end adjacent the gas inlet end of the shell and an open end extending outwardly from the closed end of said outer tubular member at the gas inlet end of the shell, there being passage means in said inner tubular member establishing communication between said chamber and said inner tubular member, and wherein said sheet has an annular configuration so as to be received in said annular chamber.
 8. A muffler as set forth in claim 7 in which said inner tubular member has an intermediate tubular member disposed concentrically outwardly thereof, said intermediate tubular member being disposed concentrically inwardly of said outer tubular member to divide said chamber into inner and outer annular zones, said intermediate tubular member having both of its ends closed and passage means therein establishing communication between said zones; and wherein said sheet is defined by a first annular section slidably insertable in said inner zone and a second annular section slidably insertable in said second zone.
 9. A muffler as set forth in claim 1 wherein said shell is a unitary member that is circular in cross section at the gas inlet end thereof, and that is rectangular in cross section at the gas outlet end thereof.
 10. A muffler as set forth in claim 1 wherein a coating is provided on at least a portion of said sheet for controlling the harmful effluent in the exhaust gas.
 11. A muffler as set forth in claim 1, in which said shell is defined by inner, intermediate and outer tubular members positioned in telescoping relationship and cooperating to define inner and outer coaxial, annular zones; first and second passage means placing adjacent ends of respective zones in communication with said inlet end and said outlet end; and third passage means spaced from said first and second passage means and placing said zones in communication with each other.
 12. A muffler as set forth in claim 11 in which one of said annular zones has aN annular section of said sheet disposed therein.
 13. A muffler as set forth in claim 11 including the further improvement of means cooperating with said outer tubular member between the inlet of said shell and said annular zones to define a resonator chamber.
 14. A muffler as set forth in claim 11 in which said intermediate tubular member has a tapered element closing the inlet end thereof, said tapered element cooperating with said outer tubular member to define said first passage means and said inner tubular member to define said second passage means; said third passage means includes apertures spaced from said opposite end whereby the outlet end of said outer annular zone defines a pulse buffer zone; and said outer tubular member is rectangular in cross section between the outlet end of said inner tubular member and the outlet end of said muffler, said rectangular section having said sheet therein; and in which said muffler includes means defining a resonator chamber between said inlet end and said tapered element and including an apertured sleeve coaxial with said outer tubular member.
 15. A muffler as set forth in claim 14 in which said last means includes an integral extension at the inlet end of said intermediate tube, said extension having an outwardly tapered portion at the free end engaging said outer tubular member and having a plurality of apertures communicating with a chamber defined between said extension and said outer member; said intermediate tubular member has a second outwardly flared portion engaging said outer tubular member at a point axially spaced from said third passage means to define said annular pulse buffer zone adjacent the remote end of said outer annular zone; and said inner tubular member has a forwardly tapered element closing the forward end thereof for deflecting gases from said intermediate tubular member toward said outer annular zone.
 16. A muffler as set forth in claim 15 including the further improvement of an annular section of said sheet supported adjacent the forward end of said resonator chamber, said annular section supporting a catalyst for effecting the chemical composition of the exhaust gases.
 17. A muffler as defined in claim 11 in which said inner tubular member has a tapered element closing the inlet end portion; said inner tubular member has an outwardly deformed portion spaced from said closed end and cooperating with said intermediate tubular member to define the remote end of said inner annular chamber; said intermediate tubular member has an inwardly deformed portion cooperating with said inner tubular member adjacent said closed end portion to define the forward end of said inner annular chamber, said intermediate tubular member extending beyond said closed end portion and having spaced outwardly deformed portions cooperating with said outer tubular member to define a resonator chamber, said intermediate tubular member having openings placing said resonator chamber in communication with said inlet end; said first passage means is located adjacent said inwardly deformed portion of said intermediate tubular member to place said outer annular zone in communication with said inlet end; and said third passage means is spaced from the opposite end of said outer annular zone to define a sound-attenuating buffer zone.
 18. A muffler as defined in claim 1 in which said shell comprises a circular member having an annular section of said sheet located in contacting engagement with the inner surface of an intermediate portion thereof; said circular member being deformed to a rectangular section adjacent the outlet end thereof and having a section of said sheet disposed therein; and said circular member being bent at the opposite end of said intermediate portion whereby said annular section is maintained in substantially fixed position relative to said shell.
 19. A muffler as defined in claim 1 in which at least a section of said sheet has said ribbon portions extending transversely of said shell.
 20. A mUffler as defined in claim 1 in which said sheet is slidably inserted in said shell and said ribbon portions are disposed at an angle with respect to the width of said shell.
 21. A muffler as defined in claim 1 in which said shell comprises an outer tubular member having reduced area portions on opposite ends thereof; first and second annular sections of said sheet located within said outer tubular member and having adjacent ends in axially spaced relation, said first section having its opposite end in engagement with an abutment defined by one of said reduced area portions; a tube having an intermediate portion in sealing engagement with said reduced area portion, said tube having a free end extending into said tubular member and engaging the opposite end of said second annular section, said tube cooperating with said tubular member to define a second resonator chamber in communication with the inside of said tube.
 22. A muffler comprising outer tubular member having a forward inlet end and a rear outlet end; an intermediate and an inner tubular member; said tubular members cooperating to define substantially coextensive inner and outer annular zones; first and second passage means communicating with adjacent ends of said inner and outer annular chambers and connecting a first of said zones with said inlet end and a second of said zones with said outlet end; third passage means interconnecting said zones, said third passage means being spaced from the opposite end of said first of said zones whereby exhaust gases received through the inlet end of said muffler pass through said first passage means and move along a path in one of said zones and pass through said third passage means and move along the other of said zones in the opposite direction and whereby the area between said third passage means and said first of said zones acts as a sound-deadening pulse buffer zone to absorb sound noises from said gases; and a sound-attenuating sheet in said outer tubular member between said inlet and outlet ends.
 23. A muffler as defined in claim 22, including a tapered member closing the forward end of said inner tubular member with said first and second passage means located adjacent said end and respectively placing the forward end of said outer annular zone in communication with said inlet end and the forward end of said inner annular zone in communication with said outlet end; and in which said intermediate tubular member extends forwardly of said inner tubular member and has spaced portions cooperating with said outer tubular member to define a resonator chamber, and said intermediate tubular member has openings between said portions placing said resonator chamber in communication with said inlet end.
 24. A muffler as defined in claim 23, including the further improvement of said inner and intermediate tubular members each having first and second spaced, substantially coextensive outwardly deformed portions adjacent the rear end of said annular zones defining second and third spaced resonator chambers in communication with said inner tubular member; said inner tubular member having an inwardly deformed portion substantially closing said inner tubular member adjacent the rear end of said second resonator chamber; said tubular members cooperating to define second annular inner and outer zones between said second and third resonator chambers, said second annular inner and outer zones respectively in communication at the forward ends thereof with said inner tubular member upstream and downstream of said inwardly deformed portion; said intermediate tubular member having radially spaced openings placing said second outer annular zone in communication with said inner annular zone spaced from the rear end of said second outer annular zone to define a second buffer zone and said communication between said second inner annular zone and said inner tubular member being spaced from the forward end of said second inner annular zone to define a third pulse buffer zone.
 25. A muffler as dEfined in claim 22 in which said intermediate member has a forwardly tapered closed end which cooperates with said outer tubular member to define said first passage means and said inner tubular member to define said second passage means.
 26. A muffler as defined in claim 25 in which said inner tubular member extends beyond the rear end of said intermediate tubular member and in which said outer tubular member is circular in cross section and the outlet end thereof is rectangular in cross section and has a section of said sound-attenuating sheet therein; and in which said outer tubular member has an apertured sleeve cooperating with said outer tubular member to define a resonator chamber between said inlet end and said first passage means.
 27. A muffler as defined in claim 22 in which said inner tubular member has a forwardly tapered element adjacent the rear end of said zones; said first and second passage means being located adjacent said tapered element and connecting said inlet end to said inner annular zone and said outlet end to said outer annular zone; said intermediate tubular member terminating at the forward end spaced from the forward end of said outer annular chamber and cooperating with said inner tubular member to define said third passage means.
 28. A method of forming a muffler having an inlet end and an outlet end for exhaust gases and a sinuous flow path for said gases between said ends by deforming inner, intermediate and outer tubes which comprises the steps of deforming said intermediate tube outwardly at first, second and third axially spaced locations which cooperate with said outer tube to produce first and second axially spaced chambers when said tubes are arranged in telescoping relation; forming apertures in said intermediate tube to place the inside of said tube in communication with said first chamber when the tubes are arranged in telescoping relation; producing first passage means through said intermediate tube adjacent one end of said second chamber and second passage means spaced forwardly of the second outward deformation; deforming at least one of said intermediate and inner tubes to produce a third chamber having one end in communication with said second passage means when said tubes are arranged in telescoping relation; closing one end of said inner tube and producing third passage means adjacent said closed end; telescoping said inner tube into said intermediate tube to locate said closed end adjacent said first passage means and said deformed portions of said at least one of said intermediate and inner tubes to produce said third chamber; telescoping said intermediate tube into said outer tube to produce said first and second chambers; locating a gas-deflecting and sound-deadening sheet between the inlet and outlet ends of said outer tube; and deforming opposite ends of said outer tube to enclose said intermediate and inner tubes between said opposite ends and produce a sinuous flow path for exhaust gases into one end of said intermediate tube with said first chamber acting as a resonator chamber, through said second chamber with the opposite end of said second chamber acting as a sound-deadening buffer zone, through said second passage means and along said third chamber, and through said third passage means and said inner tube to said outlet.
 29. A method as defined in claim 28 in which said outlet end of said outer tube is deformed to a rectangular cross section and at least a section of said sheet is located in said rectangular section.
 30. A method as defined in claim 28 in which said deforming of at least one of said intermediate and inner tubes includes inwardly deforming spaced portions of said intermediate tube to engage said inner tube in the telescoped position.
 31. A method as defined in claim 28 in which said outward deforming of said intermediate tube includes outward deformation at a fourth location axially spaced from said third location and inward deformation adjacent said first outward deformation; and in whicH said inner tube is outwardly deformed at first and second locations and is inwardly deformed adjacent said first outward deformation; the further improvement of producing apertures in each of said outwardly deformed portions of said inner tube and first and second groups of openings on opposite sides of said inwardly deformed portion; and producing third and fourth groups of openings respectively adjacent said third and fourth outwardly deformed portions of said intermediate tube; said third and fourth outward deformations of said intermediate tube cooperating with said first and second outward deformations of said inner tube to define second and third resonator chambers and outer and inner annular zones in the assembled condition; said first group of openings being aligned to define an inlet to said outer annular zone; said second openings in said intermediate tube connecting said zones; and said inwardly deformed portion of said inner tube substantially closes said tube whereby the flow path continues through said outer and inner annular zones and through said inner tube to said outlet end.
 32. A method of forming a muffler having an inlet end and an outlet end for exhaust gases and a sinuous path between said ends for said gases by deforming inner, intermediate and outer tubes which comprises deforming and telescopingly positioning said tubes to produce substantially coextensive outer and inner coaxial annular zones respectively defined between said outer and intermediate tubes and said intermediate and inner tubes; placing adjacent ends of said zones in communication with said inlet and outlet ends, respectively; producing passage means spaced from said adjacent ends of said zones to place said zones in communication with each other whereby gases received from the inlet end flow in opposite directions in said annular zones to produce said sinuous path and the opposite end of the annular zone produces a sound-attenuating buffer zone for the exhaust gases; and locating a sound-attentuating member between said inlet and outlet ends of said muffler.
 33. A method as defined in claim 32 further including the step of closing said inner tube adjacent the ends of said annular zones which are remote from said inlet end of said muffler; placing said inner annular zone in communication with said inlet end adjacent the inlet side of said closed portion and said outer annular zone in communication with the outlet side of said closed portion; terminating said intermediate tube spaced from the end of said outer annular zone and from said inner and outer tubes; and locating an annular section of said sound-attenuating member in one of said annular zones whereby the exhaust gases flow along said inner tube to said closed portion, towards said inlet end along said inner annular zone and towards said outlet end along said outer annular zone and whereby said adjacent end of said outer annular zone acts as said sound-attenuating buffer zone.
 34. A method as defined in claim 32 including the further step of producing a closed tapered portion on the inlet end of said intermediate tube which cooperates with said outer tube to connect the outer annular zone to said inlet and with said inner tube to connect said inner annular zone with said outlet.
 35. A method as defined in claim 32 including the further steps of producing a closed forward taper on the inlet end of said inner tube; inwardly deforming said intermediate tube into engagement with said inner tube; placing said outer annular zone in communication with said inlet end and said inner annular zone in communication with said outlet end on opposite sides of said closed forward taper; extending said intermediate tube from said closed forward taper and outwardly deforming spaced portions of the extension into engagement with said outer tube to produce a resonator chamber in communication with said inlet end.
 36. A method of forming a muffler from outer, intermediate and inner tubes, each having forward and rear ends and, respectivelY, having first, second and third diameters which comprises: the steps of deforming said intermediate tube at first and second axially spaced locations adjacent said first end to substantially said first diameter, and third and fourth axially spaced locations; deforming one of said intermediate and inner tubes at axially spaced first and second points to the diameter of the other of said tubes; producing passage means at axially spaced locations from the inside to the outside of said intermediate tube; closing one end of said inner tube and producing flow communication through said inner tube adjacent said closed end; positioning said tubes in telescoping relation with the deformations of the intermediate tube cooperating with the outer tube to define a resonator chamber and an outer annular zone between said outer and intermediate tubes, and the deformations of the tubes cooperating to define an inner annular zone; said passage means in said intermediate tube placing the intermediate tube in communication with said resonator chamber and the forward end of said outer annular zone, said passage means also placing the remote end of said outer annular zone in communication with said inner annular zone at the remote end thereof. 